1. Field of the Invention
The present invention relates to a computer-readable medium storing a display control program and a mobile terminal using the display control program, where the display control program controls information displayed on both of a built-in display and an external display device.
2. Description of the Related Art
Recently, the technology of manufacturing display devices (which display characters and images) has dramatically advanced, and various types of display devices have been developed. For example, the recently developed display devices include a type which realizes a high frame rate and is suitable for display of dynamic images, a type which has a large display area and realizes high resolution, a lightweight portable type, and a nonvolatile type which maintains the displayed image even after being powered off. Such display devices of various types are being properly used according to the purpose.
Incidentally, the portable display devices such as mobile phones, PDAs (personal digital assistants), laptop computers, and the like have a compact, lightweight built-in display for realizing the portability. When content is required to be displayed in a large display area or to the view of people other than the user of each portable display device, the portable display devices may be connected to an external display device. In this case, the user operates the portable display device to select a content item and display the selected content item on both of the built-in display and the external display device. In addition, the user can further operate the portable display device to display another content item associated with the currently displayed content item.
However, in the case where the display area of the built-in display is smaller than the display area of the external display device, the convenience of operation of the display screen deteriorates. That is, when screen data is produced so as to fit the display area of the external display device, it is impossible to display on the built-in display the produced screen data as they are. Therefore, the built-in display can display only a reduced image or a portion of the produced screen data. In the case where the built-in display displays the reduced image of the produced screen data, the size of displayed characters is reduced, so that it is difficult to identify with the naked eye an item to be operated. On the other hand, in the case where the built-in display displays only a portion of the produced screen data, it is necessary to scroll the screen of the built-in display so that an item to be operated is displayed within the screen of the built-in display, since only the items displayed within the screen can be operated in most of the conventional portable display devices.
Further, according to a known technique as disclosed, for example, in Japanese Unexamined Patent Publication No. 10-039981, a code is assigned in advance to each of items which can be operated, and each item can be operated by simply inputting the code assigned to the item. For example, a number is assigned in advance to each hyperlink in an HTML (HyperText Markup Language) document. When a number is inputted, displayed information is switched by tracing a hyperlink corresponding to the inputted number. When this technique is used, it is possible to perform a screen operation at the sight of the screen of an external display device irrespectively of the information displayed on the built-in display at that time, and therefore reduce the burden of the operation imposed on the user.
However, the above technique disclosed in Japanese Unexamined Patent Publication No. 10-039981 has a drawback that operation errors by the user are likely to occur. This is because the portion of the portable display device through which the operational input is done is located apart from the external display device on which the item to be operated can be confirmed. In order to prevent the operation errors by the user, it is preferable that the user can perform the operation at the sight of the built-in display, which is located near the portion of the portable display device through which the operational input is done.